CN217214720U

CN217214720U - Infrared focal plane detector with latticed common electrode structure

Info

Publication number: CN217214720U
Application number: CN202122857178.6U
Authority: CN
Inventors: 唐鑫; 刘雁飞
Original assignee: Smic Recheng Technology Beijing Co ltd
Current assignee: Smic Recheng Technology Beijing Co ltd
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-08-16
Anticipated expiration: 2031-11-19

Abstract

The present disclosure relates to an infrared focal plane detector with a grid-like common electrode structure. The detector includes: the array type pixel electrode is arranged on the electrode circuit substrate; the grid-shaped common electrode is arranged on the electrode circuit substrate, each pixel electrode in the array-type pixel electrodes is surrounded by one grid of the grid-shaped common electrode, and the pixel electrodes are electrically insulated from the grid-shaped common electrode; and the infrared photosensitive layer is at least filled in the lattices of the latticed common electrode. According to the infrared focal plane detector that this disclosed embodiment provided, through setting up the common electrode into latticed, the pixel electrode is established in latticed common electrode's check, and infrared photosensitive layer sets up in latticed common electrode's top, all sets up common electrode and pixel electrode in infrared photosensitive layer one side that is close to electrode circuit base in other words from this to avoid the sheltering from of electrode pair infrared light, improved the optics filling rate, be favorable to improving the SNR of detector.

Description

Infrared focal plane detector with latticed common electrode structure

Technical Field

The present disclosure relates to the field of photoelectric sensor technology, and in particular, to an infrared focal plane detector having a grid-shaped common electrode structure.

Background

The infrared detection and imaging technology has wide application in the fields of remote sensing, night vision, guidance, biomedicine, geological detection, meteorological monitoring and the like, and especially the rapid development of recent augmented reality, virtual reality, machine vision, automatic driving, wearable intelligent equipment and the like puts forward higher requirements on the infrared detection and imaging technology.

The traditional infrared detector usually adopts a vertical architecture mode to construct an infrared photosensitive element circuit structure, namely, electrode-infrared photosensitive element-electrode coupling is carried out from bottom to top (see a figure 7 later); or planar electrode-infrared photosensitive element-electrode coupling is performed on the surface (i.e. infrared photosensitive surface) of the infrared photosensitive layer (see fig. 8 hereinafter), in the two structures, because the electrode shields the infrared photosensitive element, the infrared photosensitive element receives less infrared light, so that the optical filling rate of the detector is low, and the signal-to-noise ratio of the detector is poor.

SUMMERY OF THE UTILITY MODEL

To solve the above technical problem or at least partially solve the above technical problem, the present disclosure provides an infrared focal plane detector having a grid-shaped common electrode structure, which can improve an optical fill ratio and thus a signal-to-noise ratio.

The present disclosure provides an infrared focal plane detector having a grid-like common electrode structure, the detector comprising:

the pixel electrode comprises an electrode circuit substrate, wherein an array type pixel electrode is arranged on the electrode circuit substrate;

the grid-shaped common electrode is arranged on the electrode circuit substrate, each pixel electrode in the array-type pixel electrodes is surrounded by one grid of the grid-shaped common electrode, and the pixel electrodes are electrically insulated from the grid-shaped common electrode;

and the infrared photosensitive layer is at least filled in the lattices of the latticed common electrode.

In some embodiments, one pixel electrode is disposed in each cell of the latticed common electrode;

the pixel electrode is located at the center of the lattice.

In some embodiments, each of the cells of the grid-shaped common electrode has the same area;

and/or the presence of a gas in the gas,

each of the lattices of the lattice-shaped common electrode has the same shape.

In some embodiments, in the mesh-shaped common electrode, the shape of the lattice is a regular polygon or a circle;

and the vertex angle of the regular polygon is a fillet.

In some embodiments, in the grid-shaped common electrode, a single-side line width of the grid is 0.5 μm to 2.0 μm.

In some embodiments, the infrared-sensitive layer is a monolithic thin-film structure; the infrared photosensitive layer is further covered on the side face, away from the electrode circuit substrate, of the latticed common electrode.

In some embodiments, the thickness of the mesh-like common electrode is equal to or less than 1.0 μm;

the thickness of the infrared photosensitive layer is 1-10 times of that of the latticed common electrode;

the thickness of the pixel electrode is equal to or greater than that of the grid-shaped common electrode.

In some embodiments, the electrode circuit substrate comprises a readout circuit substrate, a readout circuit substrate passivation layer, and the pixel electrode;

the pixel electrode is electrically connected with the readout circuit substrate, and the readout circuit substrate passivation layer covers the surface of the readout circuit substrate, which is not connected with the pixel electrode, and covers the side surface of the pixel electrode;

the grid-shaped common electrode is arranged on one side, away from the readout circuit substrate, of the readout circuit substrate passivation layer, and the readout circuit substrate passivation layer achieves electrical insulation between the grid-shaped common electrode and the pixel electrode.

In some embodiments, the probe further comprises:

and the packaging protective layer covers one side of the infrared photosensitive layer deviating from the latticed common electrode.

In some embodiments, the light transmittance of the package protection layer is greater than a preset light transmittance threshold.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

the infrared focal plane detector with the latticed common electrode structure provided by the embodiment of the disclosure comprises: the array type pixel electrode is arranged on the electrode circuit substrate; the grid-shaped common electrode is arranged on the electrode circuit substrate, each pixel electrode in the array-type pixel electrodes is surrounded by one grid of the grid-shaped common electrode, and the pixel electrodes are electrically insulated from the grid-shaped common electrode; and the infrared photosensitive layer is at least filled in the lattices of the latticed common electrode. The common electrode is arranged in a grid shape, the pixel electrode is arranged in a grid of the grid-shaped common electrode, and the infrared photosensitive layer is arranged above the grid-shaped common electrode, so that the common electrode and the pixel electrode are equivalently arranged on one side of the infrared photosensitive layer close to the electrode circuit substrate, the shielding of the electrode on infrared light is avoided, the optical filling rate is improved, and the signal-to-noise ratio of the detector is favorably improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is an exploded view of a film structure of an infrared focal plane detector provided in an embodiment of the present disclosure;

FIG. 2 is a schematic perspective view of the infrared focal plane detector shown in FIG. 1;

FIG. 3 is a schematic plan view of the infrared focal plane detector shown in FIG. 1;

FIG. 4 is a schematic cross-sectional view taken along line A1-A2 in FIG. 3;

FIG. 5 is a schematic diagram of the operating principle of the infrared focal plane detector shown in FIG. 4;

FIG. 6 is a schematic diagram illustrating an effective photosensitive area of an infrared focal plane detector provided by an embodiment of the present disclosure;

FIGS. 7 and 8 are schematic diagrams of the effective photosensitive area of a related art infrared focal plane detector;

FIG. 9 is an exploded view of another film layer structure of an infrared focal plane detector provided by an embodiment of the present disclosure;

FIG. 10 is a schematic perspective view of the infrared focal plane detector shown in FIG. 9;

FIG. 11 is a schematic cross-sectional view of the infrared focal plane detector shown in FIG. 9;

FIG. 12 is a schematic diagram of the operation of the infrared focal plane detector shown in FIG. 11;

fig. 13 is a schematic flow chart of a method for manufacturing an infrared focal plane detector according to an embodiment of the present disclosure.

10, an infrared focal plane detector with a grid-shaped common electrode structure, which may also be referred to as an "infrared focal plane detector", an "infrared detector" or a "detector" for short; 110. an electrode circuit substrate; 120. a grid-like common electrode, which may also be referred to as "common electrode" for short; 130. an infrared photosensitive layer; 140. packaging the protective layer; 111. a readout circuit substrate; 112. reading out the circuit substrate passivation layer; 113. a pixel electrode; 131. a first band photosensitive pixel; 132. and a second waveband photosensitive pixel.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced in other ways than those described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.

In the related art, the infrared focal plane detector can be divided into a plurality of different types of infrared focal plane detectors according to the difference in the aspects of materials, structures, detection ranges, detection principles and the like. The infrared focal plane detector can be roughly divided into two types according to the connection structure of the infrared focal plane detector and the reading circuit substrate: one is an infrared focal plane detector made of bulk semiconductor materials (such as mercury cadmium telluride (HgCdTe), indium telluride (InSb), indium arsenide (InAs) and the like), which needs to adopt a key process (i.e. indium column flip interconnection process) to couple an infrared detector array and a CCD (or CMOS) shift register (i.e. a readout circuit) with each other, so as to obtain an infrared focal plane detector chip with high quantum efficiency and high performance; the other type is a colloid quantum dot infrared detector and an organic semiconductor infrared detector which are emerging in recent years, and an infrared focal plane detector is obtained by directly coupling and connecting an infrared photosensitive element surface and an electrode of a reading circuit substrate without adopting an indium column flip interconnection process.

Among the two types of infrared focal plane detectors, firstly, the infrared focal plane detector which needs to adopt the indium stud flip-chip interconnection process generally has the problems of non-uniformity and blind pixels and difficulty in manufacturing large-scale infrared focal plane detector arrays. Specifically, the preparation process of the infrared focal plane detector adopting indium column flip interconnection mainly comprises the following steps: cleaning, preparing a photosensitive element table board, preparing a Si-based reading circuit, preparing an electrode, growing an In column, inverting and interconnecting, thinning a substrate and testing packaging. The basic process is that indium columns are grown on a photosensitive surface pixel and a silicon-based circuit by adopting a molecular epitaxial growth technology, and then the substrate of the silicon-based reading circuit and the indium columns on the infrared photosensitive surface are mutually connected in a 'back-off' butt-welding way; or digging a hole on the silicon-based circuit substrate, and enabling the indium columns on the infrared photosensitive surface to be reversely buckled on the annular holes. In the flip interconnection process, the requirements of indium column growth and interconnection process are strict, and if the indium columns are not uniformly grown or the indium columns are connected in a flip welding manner, the signal response of the infrared detector is not uniform; if the indium columns are broken during the growth period or in the flip-chip bonding process, the infrared detector has blind pixels; especially in a non-refrigeration infrared focal plane detector, repeated temperature impact in the using process can cause indium columns to break to form blind pixels or increase imaging nonuniformity, and the phenomenon is particularly remarkable in a large-area array infrared focal plane detector and is an important factor for restricting the development of a large-scale infrared focal plane detector array.

Meanwhile, the optical transmittance of the infrared focal plane detector is low by combining the process. Specifically, in the above process flow, the infrared photosensitive surface is flipped on the base of the readout circuit, and in order to allow the infrared light to penetrate through the base (i.e. the substrate) and the lower electrode layer to irradiate onto the infrared photosensitive surface, the substrate of the infrared photosensitive surface must be subjected to a "substrate thinning" process, in which the substrate is thinned enough to allow the infrared light to penetrate as much as possible. However, the infrared light still loses part of energy through the substrate and the lower electrode layer, resulting in low optical transmittance.

Meanwhile, due to the complex preparation process, the production cost is high, the yield is low, and the large-scale application of the infrared focal plane detector is restricted.

Secondly, for the infrared focal plane detector which does not need to adopt an indium column flip interconnection process, the problems of complex process, high cost and low yield still exist due to the problems of the structure and the process flow. In addition, there is a problem of low optical fill factor. Specifically, an infrared photosensitive element circuit structure is constructed in a vertical architecture mode, namely, electrode-infrared photosensitive element-electrode coupling is performed from bottom to top (see fig. 7 later), or planar electrode-infrared photosensitive element-electrode coupling is performed on the surface of an infrared photosensitive surface (see fig. 8 later); this can cause a reduction in the optical fill factor of the detector due to the blocking of the electrode from the infrared light. With reference to fig. 7 and 8, the infrared sensitive surface area not blocked by the electrode is an area capable of effectively receiving infrared radiation, and the infrared sensitive surface area blocked by the electrode is an area incapable of effectively receiving infrared radiation. The area that can effectively receive the infrared radiation is small, resulting in a low optical fill factor.

In addition, for some pixilated infrared focal plane detectors, a vertical structure of bottom electrode-infrared photosensitive element-top electrode is adopted on the circuit structure of the infrared photosensitive plane from bottom to top. However, because of the inherent plane shape of the infrared focal plane detector, the distance from the top electrode of the pixel at the central position to the interface for reading signals is longer than the distance from the top electrode of the pixel at the edge position to the interface for reading signals, so that the uniformity of reading electrical signals is poor due to different path lengths when the detector works.

To at least one of the above problems, the embodiments of the present disclosure provide an infrared focal plane detector with high imaging uniformity and a grid ground electrode structure without flip-chip bonding, which is implemented based on the current novel infrared materials, such as infrared colloidal quantum dots. Specifically, the infrared focal plane detector with high imaging uniformity is prepared by forming a grid-shaped common electrode on an electrode circuit substrate with array-type pixel electrodes and preparing an infrared photosensitive layer on the grid-shaped common electrode and the array-type pixel electrodes surrounded by the grid-shaped common electrode in an ohmic contact mode.

Wherein, pixel electrode through setting up array is surrounded by latticed common electrode, and the two all is located the below on infrared photosensitive layer, and the ohmic contact structure on infrared photosensitive layer is buried completely to the electrode promptly, has avoided sheltering from of electrode to infrared photosensitive layer to be favorable to improving the optics filling rate, be favorable to improving the SNR of detector.

Meanwhile, the infrared photosensitive layer can be made of novel materials such as infrared colloid quantum dots, and compared with other bulk semiconductor material synthesis methods, the method is high in success rate, large in output, low in cost and beneficial to solving the problem of high infrared material manufacturing difficulty.

Meanwhile, the infrared photosensitive layer can adopt an integrated surface layer structure (namely an integrated thin film structure) which is matched with a latticed common electrode and a latticed reading circuit to realize pixelation of the detector during working, so that pixelation design and manufacturing of the infrared photosensitive layer are not needed, a process of pixelation of the infrared photosensitive layer is equivalently omitted, and an indium column flip interconnection process is not needed any more, so that the process is simplified, the cost is saved, and the yield is improved; and by using the structure of the array pixel electrode and the grid-shaped common electrode (namely, the ground electrode) on the electrode circuit substrate, the difference of reading signals caused by different wiring lengths at the central position and the edge position is avoided, the problem of lower uniformity during reading circuit signals is solved, high-uniformity imaging is favorably achieved, the blind pixel rate is reduced, and a large-scale infrared detector array can be manufactured.

Meanwhile, free 'electrons and holes' generated in the infrared photosensitive layer material can drift and separate under the action of a built-in electric field generated by carrier diffusion, and the detectors have higher response speed and lower driving voltage due to the rapid transfer of the electrons, so that the detectors can work under lower external bias voltage. In addition, the infrared quantum dots absorb infrared light to generate photoelectrons based on the quantum confinement effect, and have high response speed and high imaging quality.

Meanwhile, the packaging protective layer is arranged on the infrared photosensitive layer and is a transparent packaging layer, so that the optical transmittance is improved, the infrared light which can be received by the infrared photosensitive layer is increased, and the signal to noise ratio is further enhanced.

Therefore, the embodiment of the disclosure provides the infrared focal plane detector with the latticed common electrode structure, which has the advantages of low cost, simple process, high yield, high uniformity and higher optical filling rate.

Further, in the embodiment of the present disclosure, materials such as colloidal quantum dots which are synthesized in a liquid phase, controllable in volume, and adjustable in absorption band may be used, and based on a quantum confinement effect, the absorption wavelength of the quantum dots may be controlled by controlling the size of the colloidal quantum dots; meanwhile, the infrared photosensitive layer can be constructed by directly forming the colloid quantum dots into an infrared quantum dot film on the electrode circuit substrate in a spin coating, drop coating or spray coating mode after the traveling grid-shaped public electrode.

The electrode circuit substrate comprises a reading circuit substrate, a plane latticed public electrode and an array type pixel electrode are constructed between the electrode circuit substrate and the infrared photosensitive layer on the reading circuit substrate in the modes of photoetching, mask evaporation, magnetron sputtering and the like, an electric field between the pixel electrode and the latticed public electrode is utilized to absorb photoinduced carriers generated after the infrared photosensitive layer absorbs infrared energy to form photocurrent, therefore, the photocurrent generated in the whole infrared photosensitive layer is divided by the built-in electric field between the electrodes, which is equivalent to pixelating the electrodes by the grid-shaped common electrode and the array-type pixel electrodes, thereby indirectly pixelating the infrared photosensitive layer, and then the pixilated current carrying infrared image information is obtained, and finally, signal processing processes such as addressing, transferring, amplifying and the like are carried out by utilizing a CCD or CMOS mode, and a current signal is read.

The following describes an infrared focal plane array (i.e., an infrared focal plane detector) having a grid-shaped common electrode structure provided by an embodiment of the present disclosure, which is compared with the related art, and a corresponding manufacturing method thereof, with reference to fig. 1 to 13.

In some embodiments, fig. 1 is an exploded view of a film layer structure of an infrared focal plane detector provided by an embodiment of the present disclosure, fig. 2 is a schematic perspective structure diagram of the infrared focal plane detector shown in fig. 1, fig. 3 is a schematic plan structure diagram of the infrared focal plane detector shown in fig. 1, and fig. 4 is a schematic cross-sectional structure diagram along a1-a2 in fig. 3. With reference to fig. 1-4, the detector 10 includes: an electrode circuit substrate 110, wherein an array pixel electrode 113 is arranged on the electrode circuit substrate 110; a grid-shaped common electrode 120 disposed on the electrode circuit substrate 110, and each pixel electrode 113 of the array-shaped pixel electrodes 113 is surrounded by one grid of the grid-shaped common electrode 120, the pixel electrode 113 being electrically insulated from the grid-shaped common electrode 120; and an infrared photosensitive layer 130 filled at least in the cells of the grid-shaped common electrode 120.

The electrode circuit substrate 110 is provided with an array of pixel electrodes 113, and electrical signals generated by the pixel electrodes 113 in response to the received infrared light can be read out.

By way of example, fig. 3 exemplarily shows that the pixel electrodes 113 in the detector are arranged in an array of 15 rows and 15 columns, but do not constitute a limitation of the detector provided by the embodiment of the present disclosure. In other embodiments, the number and the array arrangement of the pixel electrodes 113 may also be set based on the requirement of the detector, which is not limited herein.

The grid-shaped common electrode 120 may be a ground electrode, when the power supply is externally connected, the pixel electrode 113 is connected to the positive electrode of the power supply, and the grid-shaped common electrode 120 is connected to the negative electrode of the power supply, so that an electric field directed from the pixel electrode 113 to the grid-shaped common electrode 120 is generated between the grid-shaped common electrode 120 and the pixel electrode 113, and under the action of the electric field, free carriers (i.e., photo-generated free carriers) generated in the infrared photosensitive layer 130 in response to infrared light are driven, so that the two electrodes (i.e., the pixel electrode 113 and the grid-shaped common electrode 120) capture the photo-generated free carriers, thereby generating a photocurrent.

Here, since the pixel electrode 113 is surrounded by the lattice of the grid-like common electrode 120, which corresponds to the pixel electrode 113 being surrounded by the surrounding ground electrode, the direction of the electric field directed from the pixel electrode 113 to the ground electrode is directed divergently from the pixel electrode 113 to the surrounding ground electrode.

For example, the grid-shaped common electrode 120 may be a metal electrode made of gold (Au), silver (Ag), aluminum (Al), or other conductive materials known to those skilled in the art, and is not limited thereto.

Among them, the infrared photosensitive layer 130 is used to generate free carriers in response to infrared light irradiated thereon, and may fill in the lattice of the grid-shaped common electrode 120 and also overflow the lattice to cover the grid-shaped common electrode 120, which is not limited herein and will be exemplified later.

Illustratively, the infrared photosensitive layer 130 may include an infrared quantum dot material or other infrared photosensitive materials known to those skilled in the art that can be used for film formation, and is not limited thereto. Illustratively, the infrared quantum dot material may be a semiconductor compound of group IIB-VIA such as mercury tellurium (HgTe), lead sulfide (PbS), etc., and it may be a binary compound, a ternary compound, or a quaternary compound, which may be provided based on the requirements of the detector, and is not limited herein.

Illustratively, fig. 5 is a schematic diagram of the operation principle of the infrared focal plane detector shown in fig. 4, wherein the readout circuit is exemplified by a photodiode passive pixel, a straight arrow represents a current direction, and a curved arrow represents infrared light. In conjunction with fig. 4 and 5, there is one pixel electrode 113 in each grid space (i.e., lattice) of the grid-shaped common electrode 120; when the detector 10 works, an electric field is generated in the plane direction from the pixel electrode 113 in the grid to the grid-shaped common electrode 120 where the pixel electrode is located, that is, a grid electric field is generated; the internal photoelectrons (i.e., photo-generated free carriers) generated by the absorption of infrared light in the infrared photosensitive layer 130 region in the grid region are captured by the grid electric field to generate a current signal, and the current signal is read out through a reading circuit, i.e., the infrared light information in the grid region is converted into electrical signal information, thereby completing the optical-electrical signal conversion.

As can be seen, in the detector 10, the photo-generated free carriers, i.e., photoelectrons, generated in the entire infrared photosensitive layer 130 are divided by the electric field in the planar configuration with the respective lattices of the grid-shaped common electrode 120 and the corresponding pixel electrodes 113 in the lattices. The grid-like common electrode 120 then completes the actual "pixel" structure of the infrared photosensitive elements, rather than the pixelated infrared photosensitive layer 130, thereby simplifying the structure and fabrication process of the infrared photosensitive layer 130.

It can be understood that the readout circuit manner of fig. 5 is to illustrate the operation principle by taking the circuit structure of the photodiode passive pixel as an example, but not to limit the structural scope of the readout circuit. In other embodiments, other readout circuit configurations known to those skilled in the art may be used, and may be configured based on the requirements of the detector, which is not limited herein.

Illustratively, fig. 6 shows the effective photosensitive areas of the detectors provided by the embodiments of the present disclosure, and fig. 7 and 8 show the effective photosensitive areas of two detectors in the related art, respectively. In fig. 7 and 8, the spatial phase positional relationship of the substrate material 301, the ohmic electrode 302, the isolation layer 303, the quantum dot layer 304, and the barrier layer 305 is shown, and the incident direction of infrared light and the direction of photocurrent are shown. Wherein, the larger the effective photosensitive area of the detector is, the higher the optical filling rate is, and the higher the signal-to-noise ratio is. As can be seen from comparing fig. 6-8, in the related art, the ohmic electrode 302 located above the quantum dot layer 304 (i.e., the infrared photosensitive layer) blocks a portion of the area, so that the area of the quantum dot layer 304 capable of effectively receiving infrared light is reduced, and the effective photosensitive area is smaller. In the detector 10 provided in the embodiment of the present disclosure, the pixel electrode 113 and the common electrode 120 are both disposed below the infrared photosensitive layer 130, so that the infrared photosensitive layer 130 is not shielded by the pixel electrode and the common electrode, and the area of the infrared photosensitive layer 130 that can effectively receive infrared light is larger, that is, the effective photosensitive area is larger.

The infrared focal plane detector 10 having a grid-shaped common electrode structure provided by the embodiment of the present disclosure includes: an electrode circuit substrate 110 on which array-type pixel electrodes 113 are disposed; a grid-shaped common electrode 120 disposed on the electrode circuit substrate 110, and each pixel electrode 113 of the array-shaped pixel electrodes 113 is surrounded by one grid of the grid-shaped common electrode 120, the pixel electrode 113 being electrically insulated from the grid-shaped common electrode 120; and an infrared photosensitive layer 130 filled at least in the cells of the mesh-shaped common electrode 120. The common electrode 120 is arranged in a grid shape, the pixel electrode 113 is arranged in the grid of the grid-shaped common electrode 120, and the infrared photosensitive layer 130 is arranged above the grid-shaped common electrode 120, so that the common electrode 120 and the pixel electrode 113 are equivalently arranged on one side of the infrared photosensitive layer 130 close to the electrode circuit substrate 110, and therefore shielding of the electrodes (including the common electrode 120 and the pixel electrode 113) on infrared light is avoided, the optical filling rate is improved, and the signal-to-noise ratio of the detector 10 is favorably improved. Meanwhile, the infrared detector provided by the embodiment of the disclosure adopts the above-mentioned stacking structure of the functional film layers, so that a flip-chip welding process flow is not needed, the process is simple, the cost is low, and the yield is high; meanwhile, each pixel electrode is connected to the electrode circuit substrate, so that the distances between each pixel electrode and the electrode circuit substrate are equal or equivalent, and the imaging uniformity of the detector is improved.

In some embodiments, with continued reference to fig. 4, the electrode circuit substrate 110 includes a readout circuit substrate 111, a readout circuit substrate passivation layer 112, and a pixel electrode 113; the pixel electrode 113 is electrically connected with the readout circuit substrate 111, and the readout circuit substrate passivation layer 112 covers the surface of the readout circuit substrate 111, to which the pixel electrode 113 is not connected, and covers the side surface of the pixel electrode 113; the latticed common electrode 120 is disposed on a side of the readout circuitry substrate passivation layer 112 facing away from the readout circuitry substrate 111, and the readout circuitry substrate passivation layer 112 provides electrical insulation between the latticed common electrode 120 and the pixel electrode 113.

The electrode Circuit substrate 110 may also be referred to as a "Readout Circuit and its silicon substrate," and includes a Readout Circuit (ROIC) substrate 111, an array pixel electrode 113, and a Readout Circuit substrate passivation layer 112, which together form a substrate portion of the Readout Circuit.

On the basis, a latticed common electrode 120 is arranged on the base passivation layer 112 of the reading circuit, and an infrared photosensitive layer 130 covers the latticed common electrode 120, the pixel electrode 113 and the uncovered base passivation layer 112 of the reading circuit; ohmic contact is formed between the infrared photosensitive layer 130 and the pixel electrode 113, and ohmic contact is formed between the infrared photosensitive layer 130 and the grid-shaped common electrode 120.

In the above structure, with reference to fig. 3, an independent pixel electrode 113 is disposed inside each cell of the grid-shaped common electrode 120, and the pixel electrode 113 and the grid-shaped common electrode 120 are electrically insulated from each other by the readout circuit substrate passivation layer 112.

The readout circuit substrate 111 is electrically connected to the pixel electrodes 113, and is used for reading out the electrical signals generated by the corresponding pixel electrodes 113 in response to the incident infrared light, and may be any readout circuit substrate known to those skilled in the art, and is not limited herein.

The readout circuit substrate passivation layer 112 is used for encapsulating the side surfaces of the readout circuit substrate 111 and the pixel electrode 113, and only exposes the top surface of the pixel electrode 113 away from the readout circuit substrate 111 for ohmic contact with the infrared photosensitive layer 130.

Illustratively, the material of the readout circuitry substrate passivation layer 112 may be a nitride, an oxide, an oxynitride or other insulating material known to those skilled in the art for insulation, and is not limited herein.

Illustratively, the material of the pixel electrode 113 may be a metal material such as gold (Au), silver (Ag), aluminum (Al), or other conductive materials known to those skilled in the art, and is not limited herein. Alternatively, the thickness of the pixel electrode 113 may be 100nm to 1000nm, or other optional thickness values, which are not limited herein.

In other embodiments, the electrode circuit substrate 110 may also be implemented in other structures, which is not limited herein.

In some embodiments, with continued reference to fig. 3, one pixel electrode 113 is disposed within each cell of the grid-like common electrode 120; the pixel electrode 113 is located at the center of the lattice.

Each pixel electrode 113 in the array-type pixel electrodes 113 is surrounded by one grid of the grid-shaped common electrode 120, and one pixel electrode 113 is arranged in each grid of the grid-shaped common electrode 120, that is, the number of the grids is equal to the number of the pixel electrodes 113, and the grids are in one-to-one correspondence, and each group of the corresponding pixel electrodes 113 and the grids surrounding the corresponding pixel electrode 113 form one pixel. With this arrangement, a larger number of pixels in the detector 10 can be ensured, which is beneficial for ensuring a higher resolution of the detector 10.

Further, the pixel electrodes 113 are all located at the center of the grid, and the uniformity of the electric field directed to the grid surrounding the pixel electrodes is good, so that electrons generated in all directions corresponding to the infrared photosensitive layer 130 can be captured, the signal intensity is high, and the uniformity is good.

In the embodiment of the present disclosure, the pixel electrode 113 is located at the center of the grid, which can be understood as follows: on the plane where the mesh-like common electrode 120 is located, the projection of the pixel electrode 113 on the plane is located at the very middle of the lattice surrounding it. In other embodiments, the pixel electrode 113 may also be located at other positions in the grid, and may be disposed according to the requirement of the detector, which is not limited herein.

In some embodiments, with continued reference to fig. 3, the area of each cell of the grid-shaped common electrode 120 is the same.

In combination with the above, the latticed common electrode 120 completes the actual "pixel" structure of the infrared photosensitive elements, the area of each lattice can be regarded as the area of each infrared photosensitive element, and the areas of the lattices are set to be the same, that is, the areas of the infrared photosensitive elements are the same, so that the areas of the infrared photosensitive elements in the detector are ensured to be the same, and the imaging uniformity and accuracy of the detector are improved.

In other embodiments, when the lattice areas of the latticed common electrode 120 are different, corresponding compensation may be performed during subsequent signal processing based on the relative sizes between the different areas, which is not described herein nor limited.

In some embodiments, with continued reference to fig. 3, each of the lattices of the grid-shaped common electrode 120 is the same shape.

The grid-shaped common electrode 120 has the same shape, so that the grid-shaped common electrode 120 has a strong shape regularity, the design process and the manufacturing process of the grid-shaped common electrode 120 are simplified, the manufacturing difficulty of the detector is reduced, the manufacturing cost of the detector is reduced, and the yield are improved.

In other embodiments, the grid shape of the grid common electrode 120 may be different, and may include two, three or more different shapes, and may be set according to the requirements of the detector, which is not limited herein.

In some embodiments, with continued reference to fig. 3, the shape of each of the cells of the grid-shaped common electrode 120 is the same, and the area of each of the cells is the same.

In combination with the above, by setting the shape and area of each lattice in the latticed common electrode 120 to be the same, uniformity is improved, and simultaneously, signal to noise ratio is improved, and imaging quality is improved.

In some embodiments, with continued reference to fig. 3, in the grid-like common electrode 120, the shape of the grid is a regular polygon (as in fig. 3) or a circle (not shown in the figure); optionally, the vertex angles of the regular polygon are rounded corners.

When the pixel electrode 113 is located in the center of the regular polygon or the circular grid with rounded corners, the electric field from the pixel electrode 113 to the grid is distributed uniformly, so that the driving force applied to the inner photoelectrons generated in each direction around the pixel electrode 113 is uniform, thereby facilitating the capture of the electrons generated in each direction corresponding to the infrared photosensitive layer 130, and further increasing the signal intensity and improving the uniformity.

Moreover, the vertex angles of the regular polygons are set to be fillets, so that the electric field distribution is more uniform, meanwhile, the difficulty of the preparation process of the latticed common electrode 120 is reduced, the yield and the yield are improved, and the cost is reduced.

Illustratively, the regular polygon may be a regular triangle, a square, a regular pentagon, a regular hexagon, or other regular polygons, which is not limited herein.

In other embodiments, the shape of the lattice in the latticed common electrode 120 may also be other shapes that are beneficial to achieving better uniformity of electric field distribution, which is not described or limited herein.

In some embodiments, with continued reference to fig. 3, the single-sided line width of the lattice (shown as W1 and W2, in a plane defined by the first direction X and the second direction Y) in the latticed common electrode 120 is 0.5 μm to 2.0 μm.

In the grid-shaped common electrode 120, the sides defining each grid form the edges of the grid electric field, and when infrared light irradiates the infrared photosensitive layer 130, electrons generated in the infrared photosensitive layer 130 corresponding to the edges are influenced by the grid electric field to be transferred and captured, so that as many photo-generated free carriers as possible are captured.

When the single-side line width of the lattice is too wide, the edge of the corresponding grid electric field is wide, so that the transfer difficulty of the photo-generated free carriers at the corresponding position is large. For this, the upper limit value of the single-sided line width of the lattice is set to 2.0 μm to ensure that the photo-generated free carriers at the edge position of the grid electric field can be effectively captured.

In addition, when the unilateral line width of the lattice is too narrow, the process difficulty is high, the stability is poor, and the lattice is easy to break. In contrast, the lower limit value of the unilateral line width of the grid is set to be 0.5 μm, so that the process difficulty can be effectively reduced, the stability of the grid is improved, and the probability of breakage of the grid is reduced, thereby being beneficial to ensuring that the whole structure of the detector is relatively stable and prolonging the service life of the detector.

Illustratively, the unilateral line width of the lattice can be 0.5 μm, 2.0 μm, 0.8 μm to 0.9 μm, 1.0 μm, 1.2 μm, or other selectable or selectable range of values, without limitation.

In other embodiments, the single-sided line width of the grid may also be any other value, and may be set based on the requirements of the detector, which is not limited herein.

In some embodiments, with continued reference to fig. 4, the infrared photosensitive layer 130 is a unitary thin-film structure; the infrared photosensitive layer 130 also covers the side of the mesh-shaped common electrode 120 away from the electrode circuit substrate 110.

In terms of physical structure, the infrared photosensitive layer 130 is an integrated thin film structure and is not divided into pixels; in operation of the detector, electrical pixelation and signal segmentation are achieved using the grid electric field in combination with the grid-like common electrode 120, thereby obtaining quantized and digitized image information corresponding to the infrared light.

In the embodiment of the present disclosure, the acquisition of the pixilated information is realized by combining the latticed common electrode 120 and the infrared photosensitive layer 130 of the integrated thin film structure, the pixilated design and the manufacturing of the infrared photosensitive layer 130 are not required, the process flow is simple, and the cost is low.

In some embodiments, fig. 9 to fig. 12 sequentially illustrate an exploded view, a schematic perspective structure view, a schematic cross-sectional structure view, and a schematic operating principle view of a film layer structure of another infrared focal plane detector provided by the embodiments of the present disclosure. Referring to fig. 9-12, in the infrared focal plane detector 10, the infrared photosensitive layer 130 is a split structure, which includes an array of photosensitive pixels corresponding to the array of pixel electrodes 113; wherein, the infrared photosensitive layer 130 includes at least two photosensitive pixels with different wave bands, and each photosensitive pixel is filled in a corresponding grid.

The infrared photosensitive layer 130 comprises at least two photosensitive pixels with different wave bands, so that the detector can detect infrared light with at least two different wave bands, and the film structure of the detector can be used for forming a monochromatic infrared focal plane detector and can also be used for forming a bicolor or multicolor infrared focal plane detector; further, the number of the wavelength bands and the wavelength range of each wavelength band are not limited, and the corresponding infrared photosensitive material can be used according to the requirements of the detector.

Exemplarily, in combination with fig. 9-12, in the infrared focal plane detector 10, on the grid-shaped common electrode 120 and the array-type pixel electrode 113, two photosensitive pixels of different bands are covered in a mosaic planar distribution, i.e., the infrared photosensitive layer 130 includes a first band photosensitive pixel 131 and a second band photosensitive pixel 132; in addition, in the same plane, the first band photosensitive pixels 131 and the second band photosensitive pixels 132 are arranged in a staggered manner, so that the resolution of the infrared image corresponding to the first band photosensitive pixels 131 and the resolution of the infrared image corresponding to the second band photosensitive pixels 132 are both high.

Illustratively, wavelengths at which the bichromatic detection can be realized include medium wave/medium wave infrared, medium wave/long wave infrared, short wave/medium wave infrared, short wave/long wave infrared, visible light/short wave infrared, visible light/medium wave infrared, visible light/long wave infrared, and the like, by selecting photosensitive materials of the first band photosensitive pixel 131 and the second band photosensitive pixel 132, which are not limited herein.

Exemplarily, in conjunction with fig. 11 and 12, in each grid space of the grid-shaped common electrode 120, there is one pixel electrode 113; when the detector 10 works, under the action of an external power supply, an electric field is generated in the plane direction of the grid-shaped common electrode 120 pointed by the pixel electrode 113 in the center of the grid, and internal photoelectrons generated by absorbing infrared light in the first-band photosensitive pixel element 131 or the second-band photosensitive pixel element 132 in the infrared photosensitive layer area in the grid interval are captured by the grid electric field to generate a current signal, and the current signal is read out through a reading circuit, that is, the infrared light information in the grid area is converted into electric signal information, so that the photoelectric signal conversion is completed.

It can be understood that the readout circuit in fig. 12 is a circuit structure of a photodiode passive pixel as an example to illustrate the operation principle, and does not limit the structural scope of the readout circuit. In other embodiments, other readout circuit configurations known to those skilled in the art may be used, and may be configured based on the requirements of the detector, which is not limited herein.

In some embodiments, with continued reference to fig. 4, the thickness W3 of the grid-like common electrode 120 is equal to or less than 1.0 μm; the thickness W4 of the infrared photosensitive layer 130 is 1-10 times of the thickness W3 of the grid-shaped common electrode 120; the thickness W5 of the pixel electrode 113 is equal to or greater than the thickness W3 of the grid-shaped common electrode 120.

Illustratively, the thickness W3 of the grid-like common electrode 120 may be 1.0 μm, 0.8 μm, 0.5 μm, or other selectable thickness values or selectable thickness ranges; correspondingly, the thickness W4 of the infrared-sensitive layer 130 may be 1.0 μm, 2.0 μm, 5.0 μm, or other selectable thickness values or selectable thickness ranges; correspondingly, the thickness W5 of the pixel electrode 113 may be 1.0 μm, 0.9 μm, 0.6 μm, or other selectable thickness values or selectable thickness ranges, which are not limited herein.

The thickness direction is a direction along the third direction Z, and is perpendicular to a plane defined by the first direction X and the second direction Y.

Wherein, when the thickness W4 of the infrared photosensitive layer 130 is equal to the thickness W3 of the grid-shaped common electrode 120, the infrared photosensitive layer 130 is a split structure, and the infrared photosensitive layer 130 thereof is filled in the grid of the grid-shaped common electrode 120 and is in ohmic contact with the pixel electrode 113 (as shown in the figure); when the thickness W4 of the infrared photosensitive layer 130 is greater than the thickness W3 of the mesh-shaped common electrode 120, the infrared photosensitive layer 130 is an integral thin film structure that not only fills in the cells of the mesh-shaped common electrode 120, but also overflows outside the cells and is connected to form an integral structure.

In some embodiments, with continued reference to fig. 1 or 4, the detector 10 may further include an encapsulation protection layer 140 covering a side of the infrared photosensitive layer 130 facing away from the grid-shaped common electrode 120.

The package protection layer 140 is used to package and protect other films, such as water and oxygen, so as to slow down the performance decay rate of each functional film, and ensure the overall performance stability and long service life of the detector.

Illustratively, the encapsulation protection layer 140 may be a single layer structure, which is as thin as possible to reduce absorption of infrared light, thereby facilitating improvement of light transmittance. Illustratively, the encapsulation protection layer 140 may be made of an organic polymer material, such as at least one of epoxy resin, organic glass, polymethyl methacrylate, SU-8 photoresist, and perfluoro (1-butyl vinyl ether) polymer, or an inorganic insulating material, such as silicon nitride, silicon oxide, etc.; or other insulating materials known to those skilled in the art, and is not limited herein.

In some embodiments, with continued reference to fig. 1 or 4, the light transmittance of the package protection layer 140 is greater than the preset light transmittance threshold.

By such arrangement, the package protection layer 140 is a transparent protection film layer for infrared light, and the package protection layer 140 reflects and absorbs less infrared light, so that as much infrared light as possible penetrates through the package protection layer 140 to reach the infrared photosensitive layer 130 thereunder, thereby being beneficial to increasing effective absorption of infrared light, being beneficial to improving the signal-to-noise ratio, and improving the imaging quality of infrared images.

Illustratively, the preset light transmittance threshold may be 85%, 90%, 93%, 95%, 98% or other selectable percentage values, and may be set based on the requirements of the detector, and is not limited herein.

In the infrared focal plane detector with the grid common electrode and high imaging uniformity provided by the embodiment of the disclosure, the array pixel electrodes 113 are arranged on the electrode circuit substrate 110, the pixel electrodes 113 are correspondingly surrounded by the grids of the grid common electrode 120, the pixel electrodes 113 and the grid common electrode 120 are covered with the infrared photosensitive layer 130, the infrared photosensitive layer 130 is covered with the packaging protection layer 140, and the packaging protection layer 140 is set to be a transparent protection film layer with higher light transmittance, so that the infrared photosensitive layer 130 in the detector can absorb more infrared light, thereby improving the signal-to-noise ratio; meanwhile, the pixel electrode 113 and the grid-shaped common electrode 120 are both arranged below the infrared photosensitive layer 130, so that infrared light cannot be shielded, and the optical filling rate is high; meanwhile, the array-type pixel electrodes 113 are connected to the readout circuit substrate 111 at respective positions, so that the influence of the difference of the routing loss between the central position and the edge position on the signal uniformity is avoided, and the improvement of the imaging uniformity and accuracy is facilitated.

The embodiment of the disclosure further provides a preparation method of the infrared focal plane detector, which can be used for preparing and forming any one of the infrared focal plane detectors with the grid-shaped common electrode structure in the above embodiments.

In some embodiments, fig. 13 shows a schematic flow chart of a method for manufacturing an infrared focal plane detector provided by the embodiments of the present disclosure. Referring to fig. 13, the preparation method may include:

s201, forming an electrode circuit substrate.

The electrode circuit substrate is provided with an array pixel electrode.

Exemplarily, the step may specifically include:

the method comprises the following steps: a readout circuitry substrate is provided and cleaned.

The reading circuit substrate comprises internal electric signal transfer, amplification, addressing, reading and other functional circuits.

Step two: and forming the array pixel electrodes on the read-out circuit substrate by utilizing photoetching, magnetron sputtering, vacuum mask evaporation or electron beam deposition.

The array pixel electrode is an array pixel electrode which can be read by independent address selection, and the adopted pixel electrode material is preferably Au, Ag and Al, and the thickness is 100 nm-1000 nm.

Step three: and covering the passivation layer of the reading circuit substrate to encapsulate and protect the electrode circuit substrate and only expose each pixel electrode.

And S202, forming a grid-shaped common electrode on one side of the electrode circuit substrate.

Each pixel electrode in the array pixel electrodes is surrounded by a grid of the grid-shaped common electrode, and the pixel electrodes are electrically insulated from the grid-shaped common electrode.

Exemplarily, the step may specifically include:

and forming a grid-shaped common electrode on the passivation layer of the reading circuit substrate by utilizing photoetching, magnetron sputtering, vacuum mask evaporation or electron beam deposition.

Illustratively, in the one-piece grid-like common electrode, there is one pixel electrode in each cell; the grid-shaped common electrode can be made of Au, Ag and Al, and the thickness of the grid-shaped common electrode can be 100 nm-1000 nm; taking the square shape as an example, the area size of a single lattice can be 5 μm × 5 μm to 10 μm × 10 μm, and the single-side line width can be 0.5 μm to 2 μm.

And S203, forming an infrared photosensitive layer on one side of the grid-shaped common electrode, which is far away from the electrode circuit substrate.

Wherein, the infrared photosensitive layer is at least filled in the lattices of the latticed common electrode.

Optionally, the infrared photosensitive layer uniformly covers the surface of each film layer, and is of an integrated film structure.

Illustratively, the infrared-sensitive layer can be constructed by liquid-full spray coating, spin coating, or drop coating.

Exemplarily, when the material of the infrared photosensitive layer is quantum dots, the step may specifically include:

preparing colloidal infrared quantum dots; for example, the mercuric quantum dots such as PbS, HgTe and the like are selected to prepare a colloidal quantum dot material sensitive to infrared light with the wavelength of 3-5 μm;

and (3) spraying, spin-coating or dripping on one side of the grid-shaped common electrode, which is far away from the electrode circuit substrate, by using a full-liquid method to form the infrared photosensitive layer.

Taking spraying as an example, the steps may specifically include: spraying the prepared colloidal quantum dot material for 10s to obtain a layer of quantum dot film; spraying ligand exchange liquid EDT on the quantum dot membrane for ligand exchange, wherein the reaction time is 30 s; and then dripping isopropanol on the quantum dot film for cleaning to obtain a layer of quantum dot film with the surface containing short-chain ligands. Repeating the steps for 10 times to form the infrared photosensitive layer.

Ohmic contacts are established between the infrared photosensitive layer and the array-type pixel electrodes and between the infrared photosensitive layer and the grid-shaped common electrode.

Illustratively, the detection wavelength of the corresponding detector can reach the range of 400nm to 14 μm based on the material selection of the infrared photosensitive surface layer, such as some types of colloid quantum dots.

Optionally, the infrared photosensitive layer is composed of a plurality of independent photosensitive pixels filled in the grid space.

Illustratively, this step may include: and photoetching to prepare a first waveband photosensitive pixel, and photoetching to prepare a second waveband photosensitive pixel.

The infrared photosensitive layer can adopt a photoetching pixelized quantum dot structure, and can realize the detection of incident light in the wavelength range of 400 nm-14 mu m according to the material selection and the particle size of the quantum dots. Based on this, wavelengths that can be detected by the dual-color detector including the first band photosensitive element 131 and the second band photosensitive element 132 include medium/medium wave infrared, medium/long wave infrared, short/medium wave infrared, short/long wave infrared, visible/short wave infrared, visible/medium wave infrared, visible/long wave infrared, and the like, which are not limited herein.

Illustratively, the material of the quantum dots may include perovskite, ZnSe, ZnS, ZnSe/ZnO, CdSe, CdTe, CdSe/CdS, InP/ZnS, InP/ZnSe/ZnS, InP/InAs, PbS, PbSe, PbTe, CuInS ₂ 、CuInSe ₂ And the group IIB-VIA semiconductor compound can be a binary compound, a ternary compound or a quaternary compound, can be arranged according to the requirement of the detector, and is not limited herein.

In this step, forming the quantum dot photosensitive pixel by using the photolithography process may include: and (4) directly photoetching the quantum dots or photoetching the photoresist.

The direct lithography quantum dots specifically include: the method comprises the steps of selecting a preset quantum dot short-chain ligand, forming on a table board in a spraying, ink-jet printing, spin coating and dripping mode, and finally photoetching, namely exposing corresponding pixel positions with light waves with specific frequency in a maskless mode, so that quantum dot short chains are connected with one another to enable quantum dots to be cured, and finally cleaning is carried out, and a required quantum dot structure is formed at a required pixel position. The quantum dot structures corresponding to the first waveband and the second waveband are respectively photoetched by the method, and finally the plane mosaic structure of the bicolor quantum dot is obtained.

The photoresist specifically may be: and obtaining the plane mosaic structure of the bicolor quantum dots by adopting a photoresist photoetching mode.

In other embodiments, the photosensitive pixels of at least two different wavelength bands may be formed in other manners known to those skilled in the art, which is not limited herein.

And S204, forming a packaging protective layer on one side of the infrared photosensitive layer, which is far away from the electrode circuit substrate.

Exemplarily, the step may specifically include:

and spin-coating a liquid material with a transparent window in an infrared band, such as at least one of polymethyl methacrylate, SU-8 photoresist, and perfluoro (1-butyl vinyl ether) polymer, on the side of the infrared photosensitive layer away from the electrode circuit substrate, and annealing to form a transparent protective film layer to realize packaging protection.

That is, the infrared photosensitive layer is covered with a transparent protective film layer, and the material of the film layer can adopt at least one of the materials so as to form a transparent window for the infrared band, namely, the infrared light as much as possible is allowed to penetrate through and is absorbed by the infrared photosensitive layer below the transparent window, thereby being beneficial to improving the integral absorption capacity of the infrared band and improving the detection accuracy.

To this end, an infrared focal plane detector is formed.

Thereafter, device testing may also be performed.

In the preparation method of the infrared focal plane detector provided by the embodiment of the disclosure, the planar grid-shaped common electrode and the array-type pixel electrode are constructed by using mask evaporation, photoetching, magnetron sputtering and other modes between the read-out circuit substrate and the infrared photosensitive layer, so that the electrode structure (comprising the common electrode and the pixel electrode) is arranged below the infrared photosensitive layer, and therefore, the infrared light irradiated to the infrared photosensitive layer is not shielded, the effective photosensitive area of the infrared photosensitive layer for receiving the infrared light is favorably improved, the optical filling rate is improved, the signal to noise ratio is improved, and the imaging quality of the infrared image is improved.

In some embodiments, the infrared photosensitive layer may be constructed based on colloidal infrared quantum dot materials; based on the quantum confinement effect, the absorption wavelength of the quantum dots can be controlled by controlling the size of the quantum dots, so that the infrared light of a specific waveband can be detected.

In some embodiments, the infrared photosensitive layer may be constructed by directly forming colloidal infrared quantum dots into an infrared quantum dot film on the electrode circuit substrate and the mesh-shaped common electrode by means of spin coating, drop coating, or spray coating. Therefore, the infrared photosensitive layer manufactured by a full liquid phase method can be adopted, the infrared photosensitive layer can be of an integrated thin film structure, pixelation is not needed, the process is simple, the cost is low, and the yield are high. In addition, the types of the colloidal quantum dots are various, and the correspondingly formed detector can emit infrared light with a wave band of 400 nm-14 mu m.

The grid-shaped common electrode is combined with the array-type pixel electrodes, and the infrared photosensitive layer is subjected to pixel segmentation by using an electric field between the grid-shaped common electrode and the array-type pixel electrodes, so that the infrared photosensitive layer can be of an integrated thin film structure, the dead pixel condition of the infrared photosensitive pixels of a common pixilated infrared focal plane detector does not need to be considered, and the infrared photosensitive layer is simple in process and good in performance.

And the combination of the grid-shaped common electrode, the array-type pixel electrodes and the infrared photosensitive layer ensures that the electrical signal of each divided 'photosensitive pixel' is less influenced by the length of a circuit path when being read, so that a more uniform and accurate electrical signal is obtained, a more accurate infrared signal is obtained through reverse deduction, and the improvement of the infrared imaging quality is facilitated.

In some embodiments, the grid-shaped common electrode and the array-type pixel electrodes are formed on the read-out circuit substrate by using evaporation, photoetching, magnetron sputtering or electron beam deposition, so that indium column growth and flip interconnection processes are not required, the process is greatly simplified, the cost is reduced, the reduction of 'blind pixels' is facilitated, and the infrared imaging quality is improved.

The preparation process of the grid-shaped common electrode and the array-type pixel electrode is mature; meanwhile, the infrared photosensitive layer is formed in an integrated spin coating, dripping coating or spraying manner, so that the infrared photosensitive layer and the surface material thereof are uniform, noise caused by the difference of different photosensitive pixels under pixelation is reduced, and the uniformity is improved.

The grid-shaped common electrode and the array-type pixel electrodes are completely embedded into the infrared photosensitive layer to form ohmic contact, and the infrared photosensitive layer is not shielded, so that high optical filling rate can be realized. Namely, the structure that the electrode is completely buried under the infrared photosensitive element is adopted, so that the larger optical filling rate is realized, and the absorption rate of the focal plane to infrared light is improved.

Meanwhile, the electrode is completely embedded into the ohmic contact structure of the infrared photosensitive layer, and high optical transmittance can be realized. In combination with the above, since the electrode is completely embedded under the infrared photosensitive layer, only one transparent protective film layer for encapsulation is arranged on the whole infrared photosensitive layer; therefore, the blocking of infrared light is reduced to a certain extent, and the optical transmittance of the detector is better overall.

The preparation method provided by the embodiment of the disclosure can be used for preparing a large-area array infrared focal plane detector. Specifically, in combination with the above device structure and preparation method, it can be seen that by using a larger readout circuit substrate and photoetching a larger grid-shaped common electrode, a larger large-area array infrared focal plane detector can be manufactured by a solution method.

In other embodiments, the manufacturing method provided in the embodiments of the present disclosure may also be used for manufacturing a linear array infrared focal plane detector or other types of detectors, which is not limited herein.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An infrared focal plane detector having a grid-like common electrode structure, comprising:

2. The detector according to claim 1, wherein one of said pixel electrodes is disposed in each cell of said grid-like common electrode;

the pixel electrode is located at the center of the lattice.

3. The detector according to claim 1 or 2, wherein each cell of the grid-like common electrode has the same area;

and/or the presence of a gas in the gas,

the shape of each lattice of the latticed common electrode is the same.

4. The detector according to claim 3, wherein in the grid-shaped common electrode, the shape of the grid is a regular polygon or a circle;

and the vertex angle of the regular polygon is a fillet.

5. The detector according to claim 1, wherein in the grid-like common electrode, a single-side line width of a grid is 0.5 μm to 2.0 μm.

6. The detector of claim 1, wherein the infrared photosensitive layer is a monolithic thin film structure; the infrared photosensitive layer is further covered on the side face, away from the electrode circuit substrate, of the latticed common electrode.

7. The detector according to claim 1, wherein the thickness of the grid-like common electrode is equal to or less than 1.0 μm;

8. The detector of claim 1, wherein the electrode circuit substrate comprises a readout circuit substrate, a readout circuit substrate passivation layer, and the pixel electrode;

9. The probe of claim 1, further comprising:

and the packaging protective layer covers one side of the infrared photosensitive layer, which deviates from the latticed common electrode.

10. The detector of claim 9, wherein the light transmittance of the protective encapsulation layer is greater than a preset light transmittance threshold.